CD74 and Patent ductus arteriosus: Compared with that of M/PDA, the IHC score of tumour-infiltrating follicular B cells (expressing CD74) in GSRC was higher, and the difference was statistically significant (Wilcoxon rank-sum test, p = 0.012); The IHC score of tumour-infiltrating MALT-B cells (expressing JCHAIN) in GSRC was higher, but the difference was not statistically significant (Wilcoxon rank-sum test, p = 0.154) (Fig. 6f, Supplementary Fig. 5).